I rather think that this just shows the guards universally used, rather than engaging guards used by different nations per se. The nationalities seem to be to just show the different uniforms, until the Spanish v Italian plate, which does clearly indicate fencing styles.

Then again, it is more or less accurate to show the Frenchman standing in quarte.. though I do not think tierce was particularly English, or half-circle was particularly Austrian.

At first glance it looks consistent with the list of possible guards for use with both the thrusting and cutting swords as detailed by Girard (1736,1740) which seems to be commonly repeated in treatises afterwards (especially people like De Bast for example who took all the oddities from his favourite fencing books and stuck them all together into his appendices).

--Effete Snob--"I have a sword to defend my honour. I have a stick to answer those without honour."